import java.util.Arrays;
import java.util.Scanner;

class Scratch {

	public static long mod_inv(long a, long m){
		return (a == 1 ? 1 : (1 - m*mod_inv(m%a, a)) / a + m);
	}

	public static long gcd(long a, long b){
		return b == 0 ? a : gcd(b, a % b);
	}

	public static boolean make_so(long[] as, long[] ms){
		for(int fst = 0; fst < ms.length; fst++){
			for(int snd = fst + 1; snd < ms.length; snd++){
				long gcd = gcd(ms[fst], ms[snd]);
				if(gcd == 1){ continue; }

				if(as[fst] % gcd != as[snd] % gcd){
					return false;
				}

				ms[fst] /= gcd;
				ms[snd] /= gcd;
				while(true){
					long gt = gcd(ms[fst], gcd);
					if(gt == 1){ break; }

					ms[fst] *= gt;
					gcd /= gt;
				}
				ms[snd] *= gcd;

				as[fst] %= ms[fst];
				as[snd] %= ms[snd];
			}
		}

		return true;
	}

	public static long chinese_remainder(long[] as, long[] ms){
		long prod = 1, sum = 0;
		long v = 0;

		for(int i = 0; i < ms.length; i++){
			long sub = as[i] - (sum % ms[i]);
			if(sub < 0){ sub += ms[i]; }

			v = (sub * mod_inv(prod, ms[i])) % ms[i];

			sum += (v * prod);
			prod *= ms[i];
		}

		return sum;
	}

	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			final long x1 = sc.nextLong();
			final long y1 = sc.nextLong();
			final long x2 = sc.nextLong();
			final long y2 = sc.nextLong();
			final long x3 = sc.nextLong();
			final long y3 = sc.nextLong();

			long[] as = new long[]{x1, x2, x3};
			long[] ms = new long[]{y1, y2, y3};
			final boolean so = make_so(as, ms);
			//System.out.println(Arrays.toString(as));
			//System.out.println(Arrays.toString(ms));
			if(!so){
				System.out.println(-1);
				return;
			}

			long prod = 1;
			for(final long p : ms){
				prod *= p;
			}

			final long ret = chinese_remainder(as, ms);
			System.out.println(ret == 0 ? prod : ret);
		}
	}
}